Multi-material Fabrication for Magnetically Driven Miniature Soft Robots Using Stereolithography

Abstract

Remote manipulation and controlled navigation of magnetically driven miniature soft robots make them promising robotic tools operating in hard-to-reach workspace. The functionality of robots can be enhanced by integrating multiple materials with different mechanical or magnetic characteristics. However, it remains challenging combining multiple materials along with arbitrary magnetization profile formation during fabrication. This study, from a pixel level, uses stereolithography process to precisely incorporate multiple materials with different physical properties for millimeter-scale robot printing, as well as encode discrete magnetizations for the actuating parts, which provides a customizable approach for sophisticated shape production. Complex shape transformations and dynamic motions were observed through the magnetic actuation of printed robots. With the integration of magnetoactive and non-magnetic materials, free locomotion in a liquid environment tracked by optical and ultrasonic detections was achieved by actuating a 4-arm flapping robot. Moreover, discrete patterns were formed with the combination of soft and rigid magnetic materials. Such versatility of robotic behaviors and enhanced morphing capabilities enable the creation of complex multi-material actuators and provide a promising route towards a wide spectrum of biomedical applications.